The major and minor glycoproteins derived from various bronchial secretions will be isolated. These proteins will be characterized in terms of their chemical and physicochemical properties, and the extent of their microheterogeneity will be ascertained. The amino acid sequences and the primary structures of their carbohydrate units will be established. Antibodies will be raised to monodispersed glycoproteins, and their levels in the bronchopulmonary secretions from normal individuals and patients with various pulmonary disorders will be quantitated.